University of Tasmania
Browse
Haase_whole_thesis_ex_pub_mat.pdf (1.63 MB)

Energy-efficient large medium-speed catamarans : hull form design by full-scale CFD simulations

Download (1.63 MB)
thesis
posted on 2023-05-27, 12:00 authored by Haase, M
Large medium-speed catamarans are currently under development as a new class of vessel for economically efficient and more environmentally sustainable fast sea transportation. Their design is based on current high-speed catamarans, to adopt advantages such as large deck areas and low wave-making resistance, but they will operate at lower speeds and carry a higher deadweight to obtain higher transport efficiency. They operate at speeds around the main drag hump, where the wave-making drag coefficient is at its maximum. Hence this speed range is usually avoided by boat designers no precise guidelines for hull form design of large medium-speed catamarans are present to operate efficiently in this generally unfavourable speed spectrum. Literature has been surveyed to derive hull form parameters that provide low drag for monohulls and catamaran vessels. Based on these findings a hull form family was developed with demihull slenderness ratios ranging from 9 to 15 and the hydrodynamic performance was evaluated at Froude numbers from 0.25 up to 0.49 to derive design parameters with the lowest drag and highest transport efficiency. These parameters corresponds to vessel sizes from 110 m to 190 m and speeds of 16 to 41 knots. A novel CFD-based approach has been developed to provide more accuracy to the final drag prediction at full scale. It was verified using results of model scale experiments of a 98 m and a 130 m catamaran and validated with results obtained from sea trial measurements, in deep as well as in shallow water. Furthermore, its capability to replicate the flow past a typical deep partially ventilated transom has been investigated using model scale experiments. The key advantage of this method is that the same computational mesh can be used for model-scale verification and full-scale predictions. The computational full-scale simulation approach was found to be capable of predicting the drag force within 5% of results derived from full-scale measurements and extrapolated model test data. In addition it has been shown to correctly predict steady and unsteady shallow water effects. Also the ventilation process of the transom stern has been experimentally validated and the ow feature in the stagnant zone past the partially ventilated transom was identified as a non-shedding squashed horseshoe vortex. The lowest drag can be achieved for catamarans with demihull slenderness ratios of 11 to 13 and hulls of 150 m in length provided highest transport efficiency for speeds of 20 to 35 knots at a light displacement, and 170 m and 190 m for a medium and a heavy displacement respectively. Finally, when comparing the results to contemporary large and fast catamarans carrying equivalent deadweight and travelling at the same speed, fuel savings up to 40% can be achieved if a hull of 150 m instead of 110 m length is used. This demonstrates that large medium catamarans have the potential to be a fuel-efficient alternative for a successful future of fast sea transportation.

History

Publication status

  • Unpublished

Rights statement

Copyright 2015 the Author Chapter 2 has been published in a modified version as: Haase, M., Davidson, G., Friezer, S., Binns, J., Thomas, G., Bose, N., Transaction of the Royal Institution of Naval Architects, Part A - International journal of maritime engineering, 2012. On the macro hydrodynamic design of highly efficient medium-speed catamarans with minimum resistance, 154. A3, 131-142. It has been removed for copyright or proprietary reasons Chapter 3 appears to be the equivalent of a pre-print version of an article published as: Haase, M., Zurcher, K., Davidson, G., Binns, J., Thomas, G., Bose, N., 2016. Novel CFD-based full-scale resistance prediction for large medium-speed catamarans, Ocean engineering, 111, 198-208 Chapter 4 appears to be the equivalent of a pre-print version of an article published as: Haase, M., Davidson, G., Binns, J., Thomas, G., Bose, N., 2017. Full-scale resistance prediction in finite waters: A study using computational fluid dynamics simulations, model test experiments and sea trial measurements, Proceedings of the Institution of Mechanical Engineers, Part M: Journal of engineering for the maritime environment, 23(1), 316-328 Chapter 5 appears to be the equivalent of a pre-print version of an article published by Taylor & Francis in Ship technology research on 21 April 2015, available online: http://www.tandfonline.com/10.1080/09377255.2015.1119922 Chapter 6 has been published in a modified version as: Haase, M., Davidson, G., Friezer, S., Binns, J., Thomas, G., Bose, N., Transaction of the Royal Institution of Naval Architects, Part A - International journal of maritime engineering, 2015. Hydrodynamic hull form design space exploration of large medium-speed catamarans using full-scale CFD, 157. A3, 161-174. It has been removed for copyright or proprietary reasons

Repository Status

  • Open

Usage metrics

    Thesis collection

    Categories

    No categories selected

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC